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121.
近圆轨道遥感卫星星下点轨迹的计算 总被引:3,自引:0,他引:3
根据遥感卫星轨道的特点,提出了计算近圆轨道卫星星下点轨迹的算法,并对其进行精度评估。结果表明这种算法是快捷和有效的,能够满足卫星规划阶段对轨道精度的要求。 相似文献
122.
123.
THE STUDY OF STORM RAINFALL CAUSED BY INTERACTION BETWEEN THE NON-ZONAL HIGH LEVEL JET STREAK AND TYPHOON IN THE DISTANCE 总被引:1,自引:1,他引:1
In this paper, statistics were analyzed concerning correlation between the storm rainfall far from
typhoon and non-zonal upper-level jet stream. The results show that the jet stream at 200 hPa is constantly SW
(90.2 %) during the period in which storm rainfall occurs. Rainfall area lies in the right rear regions of the jet
axes. While the storm intensifies, the jet tends to be stronger and turn non-zonal. With the MM4 model, numerical
simulation and diagnosis were carried out for Typhoon No.9711 (Winnie) on August 19 to 20, 1997.
The distant storm rainfall is tightly correlative to the jet and low-level typhoon trough. The divergence field of
jet is related to the v component. The upper level can cause the allobaric wind convergence at low level. This is
the result of the form of low-level typhoon trough and the strength of the storm. By scale analysis, it is found
that there is a branch of middle scale transverse inverse circulation in the right entrance regions behind the jet
below the 300-hPa level, which is very important to the maintenance and strengthening of storm rainfall. This
branch of inverse circulation is relative to the reinforcement of jet's non-zonal characteristics. From the field of mesoscale divergence field and non-zonal wind field, we know that the stronger symmetry caused by transverse
circulation in the two sides of the jet, rainfall’s feedback and reinforcement of jet’s non-zonal characteristics
had lead to positive feedback mechanism that was favorable of storm rainfall’s strengthening. 相似文献
124.
阿尔金山北段晚新生代山体抬升的裂变径迹证据 总被引:37,自引:0,他引:37
对阿尔金山北段阿克塞 当金山口剖面的裂变径迹研究结果表明 ,该区晚新生代 8Ma左右曾发生较快速抬升。抬升年龄的展布与阿尔金左行走滑断裂带晚期活动在该区所呈现的正花状构造相吻合。 相似文献
125.
126.
非常定自适应网格模式在台风路径数值预报中的应用 总被引:7,自引:0,他引:7
本文将作者在前文中介绍的非常定自适应网格模式用于台风路径的数值预报。由于自适应网格在台风中心附近安排了较密的网格,有效地提高了网格的分辨率,使得台风环流的结构在预报48小时以后仍能保持,其预报的路径与实况相比令人鼓舞。 相似文献
127.
128.
Abstract Apatite and zircon fission track ages from Ryoke Belt basement in northeast Kyushu show late Cretaceous, middle to late Eocene, middle Miocene and Quaternary groupings. The basement cooled through 240 ± 25°C, the closure temperature for fission tracks in zircon, mainly during the interval 74-90 Ma as a result of uplift and denudation, the pattern being uniform across northeast Kyushu. In combination with published K-Ar ages and the Turonian-Santonian age of sedimentation in the Onogawa Basin, active suturing along the Median Tectonic Line from 100-80 Ma, at least, is inferred. Ryoke Belt rocks along the northern margin of Hohi volcanic zone (HVZ) cooled rapidly through ∼100°C to less than 50°C during the middle Eocene to Oligocene, associated with 2.5-3.5 km of denudation. The timing of this cooling follows peak heating in the Eocene-Oligocene part (Murotohanto subbelt) of the Shimanto Belt in Muroto Peninsula (Shikoku) inferred previously, and coincides with the 43 Ma change in convergence direction of the Pacific-Eurasian plate and the demise of the Kula-Pacific spreading centre. Ryoke Belt rocks along the southern margin of HVZ have weighted mean apatite fission track ages of 15.3 ± 3.1 Ma. These reset ages are attributed to an increase in geothermal gradient in the middle Miocene combined with rapid denudation and uplift of at least 1.4 km. These ages indicate that heating of the overriding plate associated with the middle Miocene start of subduction of hot Shikoku Basin lithosphere extended into the Ryoke Belt in northeast Kyushu. Pleistocene apatite fission track ages from Ryoke Belt granites at depth in the centre of HVZ are due to modern annealing in a geothermal environment. 相似文献
129.
Wang Pengyun 《Acta Meteorologica Sinica》1999,13(4):474-493
The track,landfall,dynamic and thermodynamic and cloud-rain physical mesoscale structures and their evolution of typhoon HERB 1996 in 36 h from 0000 UTC 31 July to 1200 UTC 1 August 1996 were simulated by using the non-hydrostatic mesoscale model MM5.This period covered the process of typhoon HERB landfall at Taiwan and Fujian Provinces.Results show that the model successfully simulated the landfall process of typhoon HERB,revealed the most important characteristics of the mesoscale dynamic and thermodynamic and cloud-rain physical structure during its landfall.The simulated typhoon track was close to the observation.The center of cyclonic circulation simulated at 0000 UTC on 1 August 1996 (24 h integration) was located in shore near Fuqing,Fujian Province at which the typhoon was reported to landfall two hours later.It shows that strong upward motion formed by low level convergence existed in the eye-wall and subsidence at the eye.The wind field shows clear asymmetrical structure near the typhoon center.The cloud and rainband was screw-typed distributed around typhoon center,and consisted of meso-β scale rain cores.During the period of typhoon HERB staying near and passing over Taiwan,the lower cloud was developed in the eye region so that the previous clear typhoon eye on the satellite pictures became fuzzy.Observation shows that the typhoon center was "warm",but the model simulations with higher space resolution show that in the mid-troposphere the region of eye-wall with stronger upward motion and more cloud-and rain-water was warmer than the eye.During the period of typhoon passing over Taiwan and its following landfall at Fujian,the track of model typhoon deviated about 30 km northward (i.e.,rightward) because of the orographic effects of Taiwan Island,but the strength of the typhoon was not affected remarkably.The amount of rainfall on Taiwan in the 36 h simulations was enhanced more than six times by the orographic lifting of Taiwan Mountain. 相似文献
130.
Statistic and typical-year composition methods are used to study the northwest Pacific typhoon activities in relation with the EI Niño and La Niña events. The result indicates that the typhoon tends to be inactive in the EI Niño years and active in the La Niña years and it is also dependent on the onset and ending time and intensity of the events and areas of genesis of typhoons. With statistic features of the frequency of typhoon activity in the EI Niño and La Niña years and the time-lag correlation between the frequency and sea surface temperature(SST), useful information is provided for the prediction of typhoon occurrence. In addition, the singular values disassemble(SVD)method is applied to study the correlation between the geopotential field and SST field. The result shows that the air-sea coupling in the EI Niño years is unfavorable for the typhoon to develop. Which take place with a smaller number. Opposite situations are found with the La Niña years. 相似文献